1. Field of the Invention
The invention relates generally to the field of gas treatment devices. More particularly, the invention relates to gas sweetening and gas drying devices.
2. Background Art
U.S. Pat. No. 2,437,288 describes a purification and separation unit for gas mixtures comprising an absorber-regenerator system, where the absorber and regenerator columns are connected by piping through heat exchangers and water coolers, and where liquid solvent is moved by a pump. One disadvantage of the unit described in the '288 patent is low energy efficiency of the solvent circulation where pressure in the absorber is required to be higher than in the regenerator due to gas treatment conditions. See, for example, Deep Crude Conversion: Process and Ecological Aspects, Kaminski, E. F., Khavkin, V. A., Moscow, 2001. Also see, U.S. Pat. No. 3,851,041.
In the circumstances described in the foregoing publications, the operating pressure in the regenerator is substantially lower than the pressure in the absorber. Solvent recirculation is established and maintained by a circulating pump moving solvent from the regenerator to the absorber. Then, rich solvent, after contact with treated gas in the absorber under higher pressure than in regenerator, flows back to the regenerator as a result of the pressure differential between higher pressure in the absorber and lower pressure in the regenerator. The static pressure differential, as well as the kinetic energy of flowing rich solvent fluid dissipates as friction in flow control instrumentation that maintains the liquid level in the bottom of the absorber. The foregoing results in low energy efficiency of the solvent recycling circuit. The foregoing explanation is also applicable to other cases where gas compression is required.